2 Approach to the evidence review

The study involved a detailed evidence search to better
understand the current knowledge base. The evidence search used a
three-way approach.

Systematic literature search,

Call for evidence,

Review of current research grant programmes.

Certain areas of interest have already been covered by two
recent studies. First, the Department of Energy and Climate Change
(
DECC)
[1] funded co-benefits project (Smith et al., 2017) identified key
research areas and relevant literature for a
UK (and international)
context. This work provided particularly good coverage on
health-related co-benefits in the transport sector. Secondly, the
Department for Environment, Food and Rural Affairs (
Defra) funded
SPLiCE
project (2015) summarised evidence on the positive and negative
impacts of energy technologies, by conducting a 'review of
reviews'. This study, for the Scottish Government, provides an
opportunity to consider the role of quantitative models and the
implications of co-impacts for social equality in particular
detail.

2.1 Literature search and key outcomes

The literature search for the Scottish context study took place
from July to August 2016 and covered four sources:

Scopus (research articles, including articles in press, and
books)

Repec (economics articles and working papers)

ResearchGate (articles, working papers and conference
papers)

Google Scholar (all of the above)

Relevant grey literature was searched for on the websites of key
organisations including the European Environment Agency (
EEA), the
International Energy Agency (
IEA), the
World Health Organisation (
WHO) and the
World Bank. Some further references were added by 'snowballing',
i.e. adding important papers referred
to by some of the papers reviewed. A particular point of relevance
is that there is a large transport research evidence base that is
not necessarily framed as co-benefits. For example, there is
historic literature on congestion reduction that does not use a
co-benefits terminology. Where appropriate, therefore, more focused
searches were undertaken to cover these areas.

In total over 300 relevant papers were identified, with over 100
of relevance to the Scottish context. Their bibliographic details
were entered into a database. Most papers in the transport
literature as it relates to co-benefits were framed in terms of
active travel, but a number also considered energy efficiency
including electric vehicles.

2.2 Call for evidence and research grant
analysis

A call for evidence was directed at key research organisations,
identified by: the Scottish Government; from the literature search
and other networks from Scotland and the rest of the
UK. This resulted in over
fifteen submissions with responses from a broad range of
organisations. These were added to the evidence database.

A research grant analysis was undertaken to understand current
and planned research relevant to the co-benefits agenda within the
UK and internationally.
Research funding sites reviewed included the Engineering and
Physical Sciences Research Council (
EPSRC),
the Natural Environment Research Council (
NERC), the
Economic and Social Research Council (
ESRC), the
Department for Transport (
DfT) and
Scottish Government websites. Relevant examples include work funded
by the National Institute for Health Research to evaluate the
health and wellbeing impacts of major change in the urban
environment - the introduction of the M74 motorway in Glasgow and
associated urban improvements. The final outputs from the work will
be published in July 2017.

2.3 Framework for the report

Climate change mitigation in the transport sector can be framed
around a shift / reduce / improve framework (
e.g. Dalkmann and Brannigan,
2007). This approach is used in this study to reflect the broad
range of mitigation options available to the Scottish
Government.

The above framework is used to set out the literature review
findings in
Chapters
4 to 6 with an overview of results presented in
Chapter
3.
Chapter
7 summarises the main co-benefits and adverse side-effects as
they relate to air quality, noise and congestion reduction
reflecting the relevance of these outcomes across shift / reduce /
improve mitigation actions.
Chapter
8 presents conclusions and recommendations.